This invention pertains to uniquely improved level or inclination devices of the bubble or spirit-level type.
The invention is characterized by a singularly enhanced or intensified bubble image which facilitates manual viewing and also permits bubble type level devices, in association with light sensitive sensor means, to be employed with great accuracy, in automated electronic inclinometers.
Practitioners in this art have devoted substantial efforts to the development of level glass or spirit level structures with a view to enhancing or intensifying the bubble image and/or improving overall structure.
Representative of efforts in this respect are the following disclosures:
______________________________________ U.S. Pat. (Issue Date) Inventor Subject Matter ______________________________________ 674,107 J. A. Traut Reflecting contrast (May 14, 1901) surface 692,097 J. R. Wood Color contrasting (Jan. 28, 1902) background stripe 771,803 J. Bishop Color contrasting (Oct. 11, 1904) liquid and background 937,357 G. J. Bensen Housing with bubble (Oct. 19, 1909) end viewing openings 1,309,752 R. B. Bossler Opaque ball instead (July 15, 1919) of bubble 1,563,321 G. Q. Bedortha Fluorescent liquid (Sept. 6, 1921) 1,578,786 S. Weston Constant length bubble (Aug. 20, 1923) and flattened tube 1,654,248 F. Erdmann Illuminated core (Dec. 27, 1927) 2,362,872 L. T. Weagle Luminescent background (Nov. 14, 1944) 2,627,121 W. G. Moyer et al Vial seal (Feb. 3, 1952) 2,750,677 A. Wirth External prism to (June 19, 1956) facilitate viewing, with diffusion surface 3,009,254 H. S. Youngs External alignment (Nov. 21, 1961) indicia 3,694,090 H. Ohyama Colored filter with viewing prism - color refracted differently by air bubble and liquid 3,766,657 E. L. Hopkins Reflective background (Oct. 23, 1973) ______________________________________
The present invention departs totally from the spirit level teachings exemplified by prior art of the type noted above, and involves a unique adaptation and utilization of a light reflecting principal which has heretobefore been recognized, in a substantially different context, in disclosures such as Miller U.S. Pat. No. 3,737,242 (Apr. 17, 1973).
As noted in the Miller patent, a generally planar surface has markedly different light reflecting capabilities when positioned adjacent air or liquid bodies.
When a plastic body having a planar reflecting surface is positioned with the reflecting surface adjacent air, light is reflected from the surface so as to provide a relatively light appearance. When the surface is positioned adjacent a liquid, the light is diffused or refracted such that a relatively dark appearance is presented on the reflecting surface.
By departing totally from the teachings of the spirit level art as exemplified by the patents noted above, and by uniquely employing the light reflecting principals discussed above, in association with a reflecting surface defining a side portion of a bubble cavity and having at least one linear cross section (i.e., a flat or curved plane reflecting surface), the present invention, in its different aspects, produces a visually intensifed bubble image. For all practical purposes, this intensified image has the appearance of a shining, suspended globule.
With this basic objective being kept in mind, the invention will now be summarized, in relation to each of its individually significant aspects.
A first independently significant aspect of the invention is believed to reside in an improvement in a level (i.e. inclination) indicating device of the type including:
body means defining PA1 level bubble means contained within this passage means, with the level bubble means including PA1 at least one surface means having a generally linear cross section and defining a side portion of the above noted passage means; PA1 this surface means being operable to receive light and reflect therefrom, with PA1 surface means defining at least a first side portion of the aforesaid passage means, particularly when this passage means is arcuate and disposed in a generally downwardly concave configuration; and PA1 wall means disposed on a second side portion of the passage means, generally opposite to the first side portion, with the level bubble means being disposed, at least in part, generally between the first and second side portions of the passage means; PA1 the surface means being operable to receive light and reflect light toward an observer with PA1 the second wall means being visually contrasting in relation to the bubble image. PA1 light transmitting body means having generally parallel sides and defining, on one side thereof, PA1 generally segmental, frusto-conical surface means formed within the body means and defining at least a first side portion of the recess means, when the recess means is disposed in the generally downwardly concave configuration; PA1 backing means defining a second side portion of the recess means, generally opposite to the first side portion; and PA1 level bubble means contained within the recess means, this level bubble means including PA1 the backing means being relatively dark and opaque relative to the body means; PA1 the generally segmental, frusto-conical surface means being operable to receive light and reflect light toward an observer (i.e. a person or light sensing means) with PA1 said backing means being operable to diminish the visibility of the recess means and first liquid means.
fluid passage means; and PA2 first liquid means, and PA2 second fluid means defining bubble means within said first liquid means. PA2 light reflected from the surface means having a generally linear cross section, adjacent said bubble means, defining a visually intensified bubble image. PA2 light reflected from said surface means, adjacent the bubble means, defining a visually intensified bubble image, and PA2 generally arcuate recess means operable to be oriented so as to be disposed in a generally downwardly concave configuration; PA2 first liquid means, and PA2 second gas means defining gas bubble means within the liquid means, PA2 the level bubble means being disposed, at least in part, generally between the first and second side portions of the recess means, PA2 light reflected from the generally segmental, frusto-conical surface means, adjacent the gas bubble means, defining a visually intensified bubble image; and
The improvement in this first aspect of the invention reside in:
In a second independently significant aspect of the invention, the improvement in the level indicating device of the type aforenoted resides in the combination of:
A third independently significant aspect of the invention pertains to an overall level indicating device structure comprising:
In the context of each of the independently significant invention aspects noted above, additional features of relevance reside in the utilization of light diffusing means so as to tend to diffuse light impinging upon the bubble area of the device and/or in the use of indicia means which provide a desired position reflection in conjunction with the reflected bubble image.
The improved spirit level or level bubble concept of the invention is believed to afford particular utility in the context of an automated inclination measuring device wherein the light (possibly from an array of LED units) is directed against a reflecting side surface of the bubble recess or passage, with an enhanced bubble image being reflected from this surface toward a pair (or more) of light sensitive sensor means. The relative degree of light sensed by the sensor is reflective, with an unusual degree of accuracy, of the positioning of the bubble relative to the light sensing means.
Having summarized certain independently significant aspects of the invention, it is now appropriate to consider presently preferred embodiments of the invention which are depicted by way of example, but not by way of limitation, in the appended drawings.